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1. Field of the Invention
The invention relates generally to sanding boards. In particular, the invention relates to flexible tools for sanding and shaping workpieces having rounded contours.
2. Description of the Related Art
The use of abrasive-coated sheet material, or xe2x80x9csandpaperxe2x80x9d, is historically well-known. Records show that the Chinese bonded seashells to parchment with natural gum in the 13th century. Although the details of its construction are sketchy, and abrasive paper was used in Europe in the 1700""s. By the 1800""s, varnish was used to bond calcined pumice to paper.
Modern xe2x80x9csandpaperxe2x80x9d does not use sand at all. Today, extremely hard abrasive particles, known as xe2x80x9cmineralxe2x80x9d, are bound to backing material using complex resins. The mineral is selected on the basis of its durability and its ability to penetrate the surface to be abraded. Typical minerals in general use are Aluminum Oxide and Silicone Carbide. As the objects to be sanded have become more complex, various devices have been developed to apply sandpaper to the surface to be abraded. For example, U.S. Pat. No. 470,794 to Shempp is directed to a holder for supporting a piece of sandpaper in smoothing or polishing moldings and other woodwork having a curved or irregular surface. The holder includes a working edge that can be varied to fit the contour of the molding.
U.S. Pat. No. 1,570,177 to Pointer discloses a sanding block in which a large number of thin metal blades which slide relative to one another to conform to an irregular surface to be sanded.
U.S. Pat. No. 4,137,670 to Goralski shows a hand file board of the type used in repairing damage to the bodies of automobiles. The hand file provides a firm elongate planar support surface against which a sheet of abrasive material may be secured, and front and rear handles which can be used for manipulating the file to shape, sand, or scuff a surface with abrasive material supported on the file board. A central handle is provided between the front and rear handles.
U.S. Pat. No. 4,944,128 to Reiter illustrates a hand sander with an automatic slack take-up feature. The sander includes pairs of cooperating wedges to effect the degree of displacement as the base member is passed over an arcuate surface.
U.S. Pat. No. 5,203,123 to Travis is directed to a deformable sanding block having a central metallic core which is deformable, yet shape-retaining. The core is enclosed totally within an elastomeric covering which is non-abrasive.
U.S. Pat. No. 5,700,187 to Balbi sets forth a tool to stopper and abrade concave and convex surfaces. The tool includes a deformable plastic supporting base plate that may be adjusted to the shape of a surface.
While many of these patents provide sanding surfaces that conform to workpiece shapes, none has the capability to xe2x80x9cfloatxe2x80x9d, i.e., to flex when encountering changes in contour. Furthermore, known devices are relatively complex and difficult to adjust. These shortcomings, among others, make known devices unsuitable for use in many automotive bodyshop applications.
It can be seen from the foregoing that the need exists for a relatively simple and inexpensive sanding board capable of conforming to surfaces and conditions encountered in automobile body work.
These and other objects are achieved by providing a variable camber sanding board. The sanding board includes a generally planar sanding base. The sanding base is relatively flexible, and is adapted to receive sanding media in the form of abrasive sheet material. A front frame is provided on the sanding base. A front handle is mounted on the front frame, and is provided with a grip member. The front frame is pivotably linked to a mid handle via a front pivot connection. The front pivot connection includes a pin passing through coaxial bores formed in the mid handle and front frame. The mid handle includes a slotted attachment member. A bolt assembly pivotably secures the attachment member to a trigger link, forming a middle pivot connection. The trigger link includes a plurality of adjustment bores, which allow the location of the middle pivot connection to be varied by selective placement of the bolt assembly within the various adjustment bores.
The trigger link is pivotably secured to a rear handle via a rear pivot connection. The rear pivot connection includes a pin passing through coaxial bores formed in the trigger link and the rear handle, respectively. The rear handle is secured to the sanding base via a rear frame.
A slot link is pivotably secured to the rear frame via a adjustment pivot connection. The adjustment pivot connection includes a pin passing through coaxial bores formed in the slot link and rear frame, respectively. A threaded knob assembly passes through a bore located in the trigger link and a slot in the slot link. The knob assembly can be selective tightened in place in a desired position along the length of the slot link.
The invention itself, however, both as to organization and method of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings.